The CallerID prefix is a feature which allows you to tag a prefix or description to an inbound call. If you are using a voice menu you could use the CallerID prefix to highlight the option that the caller has selected.
Locate the CallerID prefix object from the left hand side, in the PBX toolbox.
Drag and drop the object to the main PBX screen. The object should appear highlighted in red, as it is not configured yet.
Next you will need to configure the CallerID prefix object, click on the settings icon in the bottom right corner of the object.
Name: A description for the callerID prefix.
Prefix: Enter in the prefix you would like to display on the handset or soft phone, that will be displayed before the callers number. For example, we could enter Sales: so the user would be able to identify that the caller has selected the sales options from the voice menu.
Alert info: This is a tag that is attached to the call details and will allow a handset to alter a few settings based on the inbound call. An example of this would be, if you require a different ring tone to be played for different numbers or options. Enter the alert info tag that you have configured into the internal ringer text of the Yealink device (under settings and ring) and select a ring tone of your choice. If the caller then selects the sales option, for example, from the voice menu not only will a Sales: tag be seen on the handset, but the ring tone will change to the selected internal ringer file.
Internal text in Yealink settings should be identical to the Alert info input in the PBX.
In the example above a distinctive ring tone will be played whenever the received call includes any of those internal ringer texts(alerts) inside of it.
Finally don't forget to Apply the Configuration when any changes are made to the CallerID prefix or associated objects.